Rechargeable power packs can supply energy to a load, and can also have energy supplied to them so that they may be reused. Rechargeable power packs, such as those providing power to a portable electronic device, are typically charged using an auxiliary charging device such as a charging dock, a wall charger or an in-vehicle charger. Charging commonly takes place at ambient room temperatures, however, in some cases, charging takes place at elevated temperatures. For example, when charging a portable electronic device in a vehicle, the temperature inside the vehicle may be elevated due to a greenhouse or other effect.